@mixin vertical-gradient($startColor, $endColor) {
    background: linear-gradient($startColor, $endColor);
}

@mixin box-shadow($dx, $dy, $r, $color) {
    box-shadow: $dx $dy $r $color;
}

@mixin text-shadow($dx, $dy, $r, $color) {
    text-shadow: $dx $dy $r $color;
}

@mixin border-radius($topleft, $topright, $bottomright, $bottomleft) {
    border-radius: $topleft $topright $bottomright $bottomleft;
}